Ion trap magnet



Jan. 23 1951 w, osTRElCHER 2,539,156

ION TRAP MAGNET Filed Jan. 19, 1949 FIG. 2

INVEN TOR.

WARREN J, cams/cum.

Patented Jan. 23, 1951 ION TRAP MAGNET Warren J. Ostreicher, New York,N. Y., assignor to Telc-Tone Radio corporation, a corporation of NewYork' Application January 19, 1949, Serial No. 71,570

I Claim. 1

This invention relates to the correction of the path of an electron beamin cathode ray tubes, such as are used in television receivers, and morespecifically to the elimination or diversion of ions caused by theelectron beam.

It is an object of the invention to provide a beam correcting unit whichis simple in construction, inexpensive in manufacture and which can beeasily mounted on or demounted from the associated cathode ray tube.

It is a further object of the invention to provide a magnetic unitpermitting the simultaneous production of at least two fields ofdifferent field intensities and/or polarities, both spaced from eachother so as to apply the different intensities to different, preferablysuccessive, portions of the path of the electron beam. In this way, aneffective elimination or deviation of the ions is provided withoutaffecting the correct movement of the electrons.

A more specific object of the invention is to provide a magnetic unitwhich is light in construction and yet strong enough to be secured tothe neck of a cathode ray tube to produce the different fieldintensities required at the different tube portions, withoutmechanically straining the envelope of the tube.

Another feature of the invention is accurately to dimension thedifferent magnetic fields without complicating the construction of themagnetlc unit.

It is, therefore, one object of the invention to derive two differentfields from a common magnet.

Still another object of the invention is to produce the different fieldintensities by differently dimensioning the pole pieces guiding the flowof the magnetic field lines.

'Additional feature of the invention is to give the pole pieces such aform as to secure effective gripping of the unit around the neck of thecathode ray tube while guiding the different field lines to theappropriate portions of the electron path.

More specifically, the different pole pieces are constructed to assumethe form of a rectangular parallelepiped, with two pairs of legs thatconvey two different fields, forming the four parallel sides of thatparallelepiped.

In another embodiment of the invention the different magnet poles orlegs of the unit are coupled directly or indirectly to a single permanent magnet and provided with different cross-sections correspondingto the different field 2 intensities required at the appropriateportions of the electron path.

These and other objects of the invention will be more clearly describedin connection with the accompanying drawing in which:

Fig. 1 shows perspectively and more or less schematically, a beamcorrecting magnetic unit embodying the invention.

Figs. 2 and 3 represent front and side views, respectively, of a moreelaborate magnetic unit adapted to be applied to the neck of the cathoderay tube of television receiver.

In Fig. 1, l is a permanently magnetized slug of cylindrical shape whichis held between a pair of magnetically conductive metal strips 2 and 3of substantially L-shape except as to arms 4 and 5 which hold slug Ibetween them. Screws 6 and I, of preferably non-magnetic material, serveto assure the mutual attachment of parts I, 2 and 3. A smaller intensityfield is derived from the common magnet l by attachinga'pair of legs 8,9 to legs 2, 3, respectively, in a crosswise manner so as to obtaindifferent magnetic fields of opposite directions in leg pairs 2, 3 and8, 9 respectively. Legs 8 and .9 may be attached, re-

. spectively, to legs 3 and 2 at points It and H by welding or any otherfixing operation assuring magnetic conductivity.

All the legs forming the pole pieces are preferably substantially ofL-shape as shown in Fig. 1 but legs 8 and 9 have a smaller cross-sectioncorresponding to the lower intensity required for re-deviating theelectron beam after it has been deviated by legs or pole pieces 2 and 3.

A washer I2 of magnetically insulating or nonconductln material isinserted at the crossing point of legs 8 and 9.

Figs. 2 and 3 show an arrangement similar to that of Fig. 1 andspecially adapted to fit around the neck of a cathode ray tube such asis used in a television receiver. The four legs or pole pieces areindicated at l3, l4 and l5, l6 respectively. The legs are alsosubstantially L-shaped but slightly curved at central portions l1, l8thereof. in accordance with the curvature of the neck of the cathode raytube to which the magnetic unit is to be fitted. At these curvedportions, the legs are provided with sleeves [9 of felt, plastic or thelike flexible or elastic material so as to assure proper setting of theunit without damage to the wall of the tube.

Nut and bolt 20, 2|, preferably also of nonmagnetic material, serve tosecure the attachment of the unit on the neck of a television tubeschematically indicated at 22.

Furthermore, legs or pole pieces may be given any desired shape,cross-section or arrangement in space, and the sequence of the differentmagnetic fields-may also be changed in any appropriate manner, withoutexceeding the scope; or

this invention.

The invention .may be applied not only to cathode raytubes fortelevision reception but also to any type of cathode ray apparatus whichis to be subjected to difierentially dimensioned or difierentiallydirected magnetic fields; and not only to deviation and re-deviation butalso to all sorts of deflection purposes, Without exceeding the scope ofthe invention.

What is claimed is:

1. In a cathode ray tube apparatus, means for producing a relativelystrong magnetic field for deviating the ray to a relatively strongextent and means for producing a relatively weak magnetic field of sucha direction as to compensate a portion of the first mentioned deviation;both said deviating means being Outside the tube having a single commonmagnet and pole pieces connected to said magnet and having differentcrosssections corresponding to the ditl'erent fields.

2. Apparatus according to claim 1 in which the pole pieces are arrangedin the form or legs at least some of which are adapted to grip aroundthe neck of the cathode ray tube.

3. Apparatus according to claim 1 in which the pole pieces are arrangedin the form of legs at least some 01 which are adapted to grip aroundthe neck of the cathode ray tube, said legs having diiTerentcross-sections and extending at one end in substantially the samedirection and at the other end coupled to the common magnet, one pair oflegs being coupled directly to said common magnet and another pair beingcoupled to said first pair.

4. In a cathode ray apparatus, at least two means for producing magneticfields of two difterent constant intensities, respectively, the twomeans being arranged at a distance from each other along the path of thecathode ray; both said means including a single common magnet andmagnetic conductors of diflerent cross-sections corresponding to thediflerent field intensities.

5. Apparatus according to claim 4 whereinthe conductors are 01substantially L-shape forming the sides 0! a rectangular parallelepiped.

6. Apparatus according to claim 4 wherein there are two pairs ofconductors having difierent cross-sections and the conductors of onepair are crossed so as to produce not only a field of an intensitydifferent from that of the other pair but also of a direction oppositeto that of the other pair of conductors, and wherein at the crossingpoint of said pair of crossed conductors,

'the latter are magnetically insulated from each other.

'7. In apparatus including a cathode ray tube which produces a compositebeam including elec-' trons and ions, a device for producing a magneticfield for separating the electrons from the ions comprising, a permanentmagnet, a first pair 01 pole pieces connected to said magnet andpositioned about a portion of said cathode ray tube for producing afirst magnetic field through said portion, and a second pair of polepieces connected to said magnet and positioned about an adjacent portion0! said cathode ray tube for producing a second magnetic field throughsaid adjacent portion, said pairs of pole pieces being of suchconfiguration that said first and second fieilds are of oppositepolarity and said first field is stronger than said second field.

W. J. OS'I'REICI-IER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,181,850 Nlcoll Nov. 28, 19392,188,579 Schlesinger Jan. 30, 1940 2,211,613 Bowie Aug. 13, 19402,274,586 Branson Feb. 24, 1942 2,472,766 Woodbridge June 7, 19492,496,127 Kelar Jan. 31, 1950 2,499,065 Heppner Feb. 28, 1950 2,500,455Fisher Mar. 14, 1950 2,513,929 Gethmann July 4, 1950 2,522,872 HeppnerSept. 19, 1950

